Phonology and hearing: could Australian Aboriginal languages be acoustically easier to hear than English by listeners with OME-induced hearing impairment?

Chronic otitis media with effusion (OME) causes hearing loss at both low (<500 Hz) and higher (>4000 Hz) frequencies. Audiometric measurements of 37 Yolngu children in an Arnhem Land community confirm previous clinical data from Pitjantjatjara children in a desert community which show that around 75-80% have a significant conductive hearing loss in at least one ear. The sound systems of Australian Aboriginal languages are lacking both in contrasts which depend on low frequency acoustic cues (high vowels, voiced obstruents) and in contrasts which depend on cues at the high frequency end of the spectrum (fricatives, aspirated stops). However, they typically have five to seven place-of-articulation contrasts, which depend on rapid spectral changes in the middle of the frequency range. Long-term average spectra of speech in Yolngu Matha and Pitjantjatjara, were compared with spectra of the same 16 individuals speaking English. There were clear quantitative spectral differences, with both Australian languages having lower amplitudes at higher frequencies (>4 kHz) and higher amplitudes between 750 Hz and 2 kHz. A test of discrimination of place of articulation and manner of articulation in quiet and in noise by 30 speakers of Yolngu Matha showed greater variation in the manner task, suggesting speakers find place discrimination easier. This contrasts with studies of English speakers that show manner cues to be more robust than place cues in noise. Thus it appears that Aboriginal languages favour sounds whose characteristics exploit precisely that area of hearing ability which is most likely to remain intact in OME.